The actor/director joins several stars and politicos in endorsing the liberal favorite and Harvard professor in her run against Republican Scott Brown.

President Obama isn't the only Democrat with major star power in his corner.

The president's former advisor and the conceptual founder of the Consumer Financial Protection Bureau, Elizabeth Warren is now the Democrats' candidate for senate in Massachusetts. Her campaign has become a second rallying point for politically-concerned celebrities -- and in a new spot from the Progressive Change Campaign Committee, Massachusetts native Ben Affleck sings the Harvard professor's praises.

"I believe she'll stand up for the working person, the everyday person, the people who have been taken advantage of by the system," he says in the new PSA. Affleck, along with fellow Massachusetts-native Matt Damon, attended a fundraiser for Warren held at JJ Abrams' studio in May. Damon also recorded a robo-call on her behalf.

The PCCC video also stars Daily Show co-creator Lizz Winstead, US Sen. Sheldon Whitehouse and Sarah Silverman. For her part, Silverman, who has produced several of her own political PSAs this season, praises Warren for standing up for people -- "people people, not corporations people."

Ron Howard, Will Ferrell, and Barbra Streisand are among the stars who have also given to the Democrat.

Warren maintains a slight poll lead in a neck-and-neck race with incumbent Sen. Scott Brown, a moderate Republican who won the late Sen. Ted Kennedy's seat in the upper chamber upon his death.